| JRPGfan said: "New Yorkers must really suck at social distancing, or it's more infectious and R0 of 2.2 is incorrect. " *edit: "3000, decent sample size, however that's not a random sample. That's testing people that still go out to stores. People that are more at risk of exposure vs those staying at home, having done their shopping earlier or get their food delivered. Also chances are you will end up testing those that frequent the stores more often vs those that do a single run to minimize exposure. I also assume it was voluntary, and those that are more careful will naturally avoid participating." |
True different numbers have been floating around for example here
https://www.forbes.com/sites/tarahaelle/2020/04/07/the-covid19-coronavirus-disease-may-be-twice-as-contagious-as-we-thought/#fa75e4f29a6a
https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article?deliveryName=USCDC_333-DM25287
A single person with COVID-19 may be more likely to infect up to 5 or 6 other people, rather than 2 or 3, suggests a new study of Chinese data from the CDC.
That's if you still want to trust Chinese data at this point :)
It's a double edged sword though:
The new study, published in the Emerging Infectious Diseases journal, shifts the R0 for COVID-19 from about 2.2 to about 5.7. With the lower number, only 55% of a population needs to be immune from COVID-19 to stop its spread through herd immunity. Herd immunity refers to enough of a population being immune to a disease that the disease cannot travel through it.
But if more people get infected from a single person with COVID-19, then more people need to be protected from the disease to stop it from continuing to spread. With an R0 of 5.7, approximately 82% of the population needs to be immune to reach herd immunity and stop the disease from spreading easily through the population, the researchers concluded.
They're lowering the incubation time as well
The new calculations also estimate the incubation period—the time from being exposed to the virus and developing symptoms—to be an average of 4.2 days, which is in line with most other estimates (though symptoms can still take up to 14 days to show up).
Doubling time of 2.3 to 3.3 days instead of 6 to 7 days.
The growth rate r is estimated to be 0.29/day (95% CI 0.21–0.37/day), corresponding to a doubling time of 2.4 days
Quite a difference.
It all means we need to be extra careful and more diligent with social distancing
We found R0 is likely to be 5.7 given our current state of knowledge, with a broad 95% CI (3.8–8.9). Among many factors, the lack of awareness of this new pathogen and the Lunar New Year travel and gathering in early and mid-January 2020 might or might not play a role in the high R0. A recent study based on structural analysis of the virus particles suggests SARS-CoV-2 has a much higher affinity to the receptor needed for cell entry than the 2003 SARS virus (21), providing a molecular basis for the high infectiousness of SARS-CoV-2.
How contagious SARS-CoV-2 is in other countries remains to be seen. Given the rapid rate of spread as seen in current outbreaks in Europe, we need to be aware of the difficulty of controlling SARS-CoV-2 once it establishes sustained human-to-human transmission in a new population (20). Our results suggest that a combination of control measures, including early and active surveillance, quarantine, and especially strong social distancing efforts, are needed to slow down or stop the spread of the virus. If these measures are not implemented early and strongly, the virus has the potential to spread rapidly and infect a large fraction of the population, overwhelming healthcare systems. Fortunately, the decline in newly confirmed cases in China and South Korea in March 2020 and the stably low incidences in Taiwan, Hong Kong, and Singapore strongly suggest that the spread of the virus can be contained with early and appropriate measures.
Even if 20% indeed already have anti bodies in NYC, it won't stop until 82% has been infected, which doesn't mean it won't reach the last 18%. It just means that you need 82% with anti bodies to prevent another wave from taking hold, hoping the anti bodies are and stay strong enough to prevent another outbreak.
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